Very low birth weight (VLBW) infants, weighing 1500 grams or less at birth, are among the highest-risk patient populations. These infants are treated in neonatal intensive care units where they are closely monitored and provided with an array of life support measures and intensive interventions. While they account for only 1 percent of births, VLBW infants account for half of infant deaths in the US each year. Yet, little is understood about the determinants of patient outcomes in the NICU. Large variations in outcomes across NICUs currently exist that cannot be explained by differences in patient characteristics. Hospital and unit characteristics, such as teaching status, volume or NICU level also explain little of the observed variation in patient outcomes across NICUs. To understand and improve patient outcomes in the NICU, other aspects of the care process must be taken into consideration. Since NICU cases are among the most nurse-intensive hospitalizations, the role of nursing in patient outcomes holds promise for explaining these variations. There is also evidence that NICUs that serve a disproportionate share of minority VLBW infants have poorer outcomes that similarly cannot be explained by patient or hospital/unit characteristics. Understanding the role of nursing therefore also holds promise for explaining and addressing observed disparities in infant outcomes for minority- serving hospitals. There is evidence from adult populations that levels of nurse staffing, nursing staff characteristics and the organization of nursing influences patient outcomes. However, there is little data on acuity-adjusted staffing in any clinical population, including the NICU. A pilot study suggests that the variation in NICUs is substantial. In this project we propose to (1) measure and describe the variation in NICUs in acuity-adjusted nurse staffing levels by developing nursing acuity weights for NICU infants and using the weights to acuity-adjust staffing levels (2) estimate the relationships among acuity-adjusted nurse staffing, the characteristics of nursing staff, the nursing practice environment and patient outcomes in the NICU and (3) explore whether acuity-adjusted nurse staffing, nursing staff characteristics, or the nursing practice environment explain the differences in patient outcomes between minority and non-minority serving hospitals. The project will use data from the Vermont Oxford Network that contains over half of the infants born in the US each year augmented by primary data collections. PUBLIC HEALTH RELEVANCE: Infant mortality in the US is concentrated among infants with very low birth weights (under 1500 grams) and disproportionately affects minority infants. This research will provide new knowledge on the effect of nursing in the NICU on mortality and morbidity among VLBW infants in the US. The project will also provide new knowledge on the potential role of nursing in explaining and addressing observed disparities in infant outcomes for VLBW infants treated in minority-serving hospitals.